Closed loop dialysis treatment using adaptive ultrafiltration rates

Abstract

A method of performing closed-loop dialysis treatment during hemodialysis is provided. The method involves determining an initial ultrafiltration rate and setting an ultrafiltration pump of a dialysis system to the determined ultrafiltration rate. A series of measurements and calculations are made to ensure that a rate of change of blood volume during treatment follows a specified profile. A threshold may be used to keep the rate of change of blood volume tracking the profile. Patient fluid dynamics may be measured in real-time and used to determine the ultrafiltration pump rate.

1 . A method for performing closed-loop dialysis treatment for a patient, comprising:
 determining, by a dialysis system, an initial ultrafiltration rate and setting an ultrafiltration pump to the determined initial ultrafiltration rate;   measuring, by the dialysis system, a total blood volume change based on the initial ultrafiltration rate;   determining, by the dialysis system, a benchmark blood volume threshold for the measured total blood volume change based on an estimated dry-weight of the patient, a currently elapsed treatment time for the closed-loop dialysis treatment, a time duration associated with the closed-loop dialysis treatment, and a start time for the closed-loop dialysis treatment;   setting, by the dialysis system, the ultrafiltration pump to a new pump rate based on comparing the determined benchmark blood volume threshold with the measured total blood volume change; and   stopping, by the dialysis system, the closed-loop dialysis treatment based on the estimated dry-weight of the patient.   
     
     
         2 . The method of  claim 1 , wherein measuring the total blood volume change comprises periodically sampling the total blood volume change at a sampling rate to determine a plurality of measured total blood volume changes, wherein each of the plurality of measured total blood volume changes is associated with a different elapsed treatment time, and
 wherein determining the benchmark blood volume threshold comprises determining a new benchmark blood volume threshold for each of the plurality of measured total blood volume changes.   
     
     
         3 . The method of  claim 2 , wherein setting the ultrafiltration pump to the new pump rate comprises cycling the ultrafiltration pump between a minimum pump rate associated with the ultrafiltration pump and the initial ultrafiltration rate based on the determined new benchmark blood volume threshold for each of the plurality of measured total blood volume changes. 
     
     
         4 . The method of  claim 1 , further comprising:
 determining a hysteresis associated with the ultrafiltration pump, and   wherein setting the ultrafiltration pump to the new pump rate is based on comparing the measured total blood volume change with the hysteresis and the determined benchmark blood volume threshold.   
     
     
         5 . The method of  claim 1 , further comprising:
 prior to measuring the total blood volume change, measuring a second total blood volume change; and   setting the ultrafiltration pump to a minimum pump rate based on comparing a second benchmark blood volume threshold with the second total blood volume change,   wherein setting the ultrafiltration pump to the new pump rate comprises setting the ultrafiltration pump from the minimum pump rate back to the initial ultrafiltration rate based on comparing the determined benchmark blood volume threshold with the measured total blood volume change.   
     
     
         6 . The method of  claim 1 , further comprising:
 prior to measuring the total blood volume change, measuring a second total blood volume change; and   setting the ultrafiltration pump to a minimum pump rate based on comparing a second benchmark blood volume threshold with the second total blood volume change,   wherein setting the ultrafiltration pump to the new pump rate comprises:
 setting, based on comparing the determined benchmark blood volume threshold with the measured total blood volume change, the ultrafiltration pump from the minimum pump rate to an ultrafiltration rate that is above the minimum pump rate and different from the initial ultrafiltration rate. 
   
     
     
         7 . The method of  claim 1 , further comprising:
 receiving clinician input indicating a target change in blood volume that is associated with the estimated dry-weight of the patient, wherein stopping the closed-loop dialysis treatment is based on a cumulative change in blood volume reaching the target change in blood volume.   
     
     
         8 . The method of  claim 1 , wherein stopping the closed-loop dialysis treatment is based on a total dialysis treatment time elapsing. 
     
     
         9 . A method for performing closed loop dialysis treatment for a patient, comprising:
 (a) setting an ultrafiltration pump to an ultrafiltration rate for an active duration;   (b) measuring a total change in blood volume during the active duration;   (c) setting the ultrafiltration pump to a minimum pump rate for a rebound duration;   (d) measuring a rebound change in blood volume for the rebound duration;   repeating steps (a)-(d) a first number of times to obtain a plurality of first measurements of the total change in blood volume and a plurality of second measurements of the rebound change in blood volume;   determining a dry weight time to meet a dry weight goal for the patient based on the plurality of first measurements of the total change in blood volume and the plurality of second measurements of the rebound change in blood volume; and   stopping the closed-loop dialysis treatment based on the determined dry weight time.   
     
     
         10 . The method of  claim 9 , further comprising:
 determining whether the treatment period is adequate to reaching the dry weight goal, wherein stopping the closed-loop dialysis treatment is based on determining whether the treatment period is adequate to reaching the dry weight goal.   
     
     
         11 . The method of  claim 10 , further comprising:
 based on the treatment period being adequate to reaching the dry weight goal, dropping a measurement of the total change in blood volume from the plurality of first measurements and a measurement of the rebound change in blood volume from the plurality of second measurements;   repeating steps (a)-(d) a second number of times to obtain one or more first additional measurements of the total change in blood volume and one or more second additional measurements of the rebound change in blood volume; and   determining a new dry weight time to meet the dry weight goal for the patient based on the one or more first additional measurements of the total change in blood volume and the one or more second additional measurements of the rebound change in blood volume   
     
     
         12 . The method of  claim 11 , wherein stopping the closed-loop dialysis treatment is based on the new dry weight time. 
     
     
         13 . The method of  claim 10 , wherein stopping the closed loop dialysis treatment is based on determining that the treatment period is not adequate to reaching the dry weight goal. 
     
     
         14 . The method of  claim 10 , further comprising:
 based on determining the treatment period is not adequate to reaching the dry weight goal, dropping a measurement of the total change in blood volume from the plurality of first measurements and a measurement of the rebound change in blood volume from the plurality of second measurements;   adjusting the ultrafiltration rate for the active duration to a new ultrafiltration rate;   repeating steps (a)-(d) a second number of times using the new ultrafiltration rate to obtain one or more first additional measurements of the total change in blood volume and one or more second additional measurements of the rebound change in blood volume; and   determining a new dry weight time to meet the dry weight goal for the patient based on the one or more first additional measurements of the total change in blood volume and the one or more second additional measurements of the rebound change in blood volume.   
     
     
         15 . The method of  claim 14 , wherein stopping the closed-loop dialysis treatment is based on the new dry weight time. 
     
     
         16 . A dialysis system for performing closed-loop dialysis treatment, comprising:
 an ultrafiltration pump;   a processor; and   a non-transitory computer-readable storage medium having processor-executable instructions stored thereon, wherein the processor-executable instructions, when executed by the processor, facilitate:
 determining an initial ultrafiltration rate and setting the ultrafiltration pump to the determined initial ultrafiltration rate; 
 measuring a total blood volume change based on the initial ultrafiltration rate; 
 determining a benchmark blood volume threshold for the measured total blood volume change based on an estimated dry-weight of the patient, a currently elapsed treatment time for the closed-loop dialysis treatment, a time duration associated with the closed-loop dialysis treatment, and a start time for the closed-loop dialysis treatment; 
 setting the ultrafiltration pump to a new pump rate based on comparing the determined benchmark blood volume threshold with the measured total blood volume change; and 
 stopping the closed-loop dialysis treatment based on the estimated dry-weight of the patient. 
   
     
     
         17 . The dialysis system of  claim 12 , wherein measuring the total blood volume change comprises periodically sampling the total blood volume change at a sampling rate to determine a plurality of measured total blood volume changes, wherein each of the plurality of measured total blood volume changes is associated with a different elapsed treatment time, and
 wherein determining the benchmark blood volume threshold comprises determining a new benchmark blood volume threshold for each of the plurality of measured total blood volume changes.   
     
     
         18 . The dialysis system of  claim 12 , wherein setting the ultrafiltration pump to the new pump rate comprises cycling the ultrafiltration pump between a minimum pump rate associated with the ultrafiltration pump and the initial ultrafiltration rate based on the determined new benchmark blood volume threshold for each of the plurality of measured total blood volume changes. 
     
     
         19 . The dialysis system of  claim 12 , further comprising:
 determining a hysteresis associated with the ultrafiltration pump, and   wherein setting the ultrafiltration pump to the new pump rate is based on comparing the measured total blood volume change with the hysteresis and the determined benchmark blood volume threshold.   
     
     
         20 . The dialysis system of  claim 12 , further comprising:
 prior to measuring the total blood volume change, measuring a second total blood volume change; and   setting the ultrafiltration pump to a minimum pump rate based on comparing a second benchmark blood volume threshold with the second total blood volume change,   wherein setting the ultrafiltration pump to the new pump rate comprises setting the ultrafiltration pump from the minimum pump rate back to the initial ultrafiltration rate based on comparing the determined benchmark blood volume threshold with the measured total blood volume change.